Locking and latching devices, apparatus, systems and methods are known for retaining a generally planar panel, such as a door, window, shutter or the like to a stationary, adjacent frame. In particular, numerous door locks and door latches are known for retaining a hinged door to a stationary door frame or to another door. One type of a known door lock includes a deadbolt that is movable between an extended, or locked, position and a refracted, or unlocked, position. One type of a known door latch includes a conventional sliding latch, also referred to as a striker plate latch. The sliding latch is biased outwardly to engage a recess provided within a door frame or within another door adjacent an edge of the door to maintain the door in a closed configuration. The common door locks and door latches are suitable for ordinary circumstances, but are usually insufficient for installations that require additional resistance against unintentional opening, for example hurricane doors intended to withstand high-force winds and security doors intended to prevent, or at least deter, crime. In those instances, it is desirable to provide one or more additional door locks or door latches that engage the door frame or the other door at an additional location.
U.S. Pat. No. 5,911,763 issued Jun. 15, 1999, to Quesada discloses a three-point lock mechanism including a central deadbolt for engaging a door jamb of a door frame adjacent a lateral edge of a door, an upper deadbolt for engaging a lintel of the door frame adjacent a top edge of the door, and a lower deadbolt for engaging a threshold, sill or floor adjacent a bottom edge of the door. A conventional deadbolt lock set for the central deadbolt has a circular plate that rotates when the lock is operated to drive upper and lower deadbolt actuation rods that actuate the upper deadbolt and the lower deadbolt, respectively. The upper and lower deadbolt actuation rods are pivotally secured to the circular plate one hundred thirty-five degrees (135°) apart from one another and at a different radius from the center of the plate. In this manner, the upper and lower deadbolt actuation rods move an equal linear travel distance when the circular plate is rotated in response to operation of the lock set. An over-center pivot at the outer end of each of the upper and lower deadbolt actuation rods simultaneously actuates the upper deadbolt and the lower deadbolt, respectively, to move between a retracted, or unlocked, position and an extended, or locked, position.
Although generally effective, the three-point lock mechanism taught by Quesada is mechanically complex, and consequently, subject to malfunction, for example jamming, or failure. Furthermore, the over-center pivots and the spatial relationship of the attachment points of the upper and lower actuation rods on the circular plate bias the deadbolts towards the locked position when the lock set is moved to the locked configuration, and conversely, bias the deadbolts towards the unlocked position when the lock set is moved to the unlocked configuration. As a result, the biasing force created by the over-center pivots and the spatial relationship of the attachment points of the actuation rods must be overcome to either lock the door lock or to unlock the door lock.
It is therefore desirable to provide a locking or latching device, apparatus, system and method that overcomes the problems, deficiencies and shortcomings associated with known locking and latching mechanisms. It is further desirable to provide a locking or latching device, apparatus, system and method that retains a generally planar panel, such as a door, window, shutter or the like, at multiple locations adjacent an edge of the panel. It is still further desirable to provide a three-way door latch that retains a hinged door to a stationary door frame at a central sliding latch, an upper sliding latch and a lower sliding latch, and simultaneously releases the sliding latches of the door in a mechanically simplistic manner that is not susceptible to malfunction or failure.
In view of the aforementioned desires, the present invention was conceived and has as an objective to provide an improved locking or latching device, apparatus, system and method for retaining a hinged door to a stationary door frame or to another door adjacent a lateral edge of the door. The invention has as a further objective to provide a three-way door latch including a central sliding latch, an upper sliding latch and a lower sliding latch that retain a hinged door to a door frame and simultaneously release the door from the door frame in response to a single operation utilizing a simplistic mechanism that is not inherently susceptible to malfunction or failure.
Various other objectives and advantages of the present invention will become apparent to those skilled in the art as a detailed description of one or more exemplary embodiments of the invention is set forth below.